It’s probably more exponential than anything given the the arc that panhard swings as the suspension cycles. Only my rear right tyre rubs the rear outer corner of the wheel arch flare/body. I’m thinking that a bracket may push the axle far enough over towards the other side to give it clearance.I have the better part of double that lift but if the differences are half of what I've noticed in a short period of time, yes worth the coin.
Edit - I don't know the geometry side well enough to know if it's linear or exponential in regards to benefit gained. If it's linear my comment stands, if it's exponential I'm not qualified to comment. I'm sure others are.